ITEM:

INFORMATIONAL ITEMS/STAFF REPORTS

 

23.

QUARTERLY IRRIGATION PROGRAM AND RIPARIAN PROJECTS REPORT

 

Meeting Date:

July 17, 2006

Budgeted

N/A

 

From:

David A. Berger,

Program/

N/A

 

General Manager

Line Item No.:

 

Prepared By:

Thomas Christensen

Cost Estimate:

N/A

 

General Counsel Approval:  N/A

Committee Recommendation:  N/A

CEQA Compliance:  N/A

 

IRRIGATION OF RIPARIAN VEGETATION: The supplemental watering of riparian restoration plantings resumed in May of 2006 at eight Monterey Peninsula Water Management District (District) riparian habitat restoration sites.  The following irrigation systems were in use in May and June: Trail and Saddle Club, Scarlett, Begonia, Schulte South, Schulte Bridge, Schulte, All Saints, and Valley Hills.

 

            Water Use in Acre-Feet (AF)

            January - March 2006   0.00 AF

            April - June 2006           0.89

            Year-to-date                  0.89 AF

 

MONITORING OF RIPARIAN VEGETATION:  During the months of May and June 2006, staff took weekly measurements of leaf water potential on target willow and cottonwood trees to provide an indication of plant water stress and corresponding soil moisture levels.  Four locations (Rancho Cañada, San Carlos, Valley Hills, and Schulte) are monitored twice a month for pre-dawn leaf water potential.  A total of 14 willows and 13 cottonwoods at these locations provide a data set of established and planted sample trees that are representative of trees in the Carmel River riparian corridor.  Soil moisture measurements are conducted at three of these sites (San Carlos, Valley Hills, and Schulte) using tensiometers.  Soil moisture values are measured at seven stations with 18-inch and 36-inch tensiometers in the soil column.  Combined with monthly readings from the District’s array of monitoring wells and pumping records for large-capacity Carmel Valley wells in the Cal-Am system, the District’s monitoring provides insight into the status of soil moisture through the riparian corridor.

 

Current monitoring results for the 2006 monitoring season to date show that riparian vegetation is below threshold stress levels.  Willows are considered severely stressed when values are 7.5 bars and above, while cottonwoods are considered severely stressed when values are 10.0 bars and above. The graphs in Exhibit 23-A and 23-B show impacts to water table elevations and riparian moisture stress in selected restoration sites in the lower Carmel Valley.

 

The types of monitoring measurements made during May through June 2006 are as follows:

 

            Monitoring Measurement                                        

 

            Dawn leaf water potential                                  (See Exhibit 23-A for trends.) 

            Soil moisture (tensiometers)                                         

            Groundwater levels (monitoring wells)   (See Exhibit 23-B for trends.) 

            Groundwater pumping (production wells)                     

           

 

 

OTHER TASKS PERFORMED SINCE MARCH 2006 REPORT:

 

1.         French Broom (Genista) Eradication in District Restoration Projects: District staff (Bekker and Lyons) have been removing an invasive weed (French broom, or genista) from the Berwick, Schulte and Red Rock Restoration Project areas.  French broom competes with native plants and can become problematic if left unchecked.

 

2.         Carmel River Watershed Conservancy Technical Advisory Committee (CRWCTAC) Meetings: Throughout the months of April, May, and June 2006, District staff (Christensen, Hampson, and Dettman) attended several CRWCTAC meetings for the prioritization of the Carmel River Watershed Action Plan (WAP). The meetings focused on initial screening and ranking to prioritize items in the WAP. Participants included NOAA Fisheries, Monterey County Water Resources Agency, Planning and Conservation League Foundation, Carmel River Steelhead Association, Big Sur Land Trust, Regional Water Quality Control Board and the Carmel River Watershed Conservancy. The group scheduled additional meetings in July and August to complete the prioritization process.

 

3.         Annual Carmel River Inspections:  On May 10th and 11th 2006, District staff inspected the Carmel River from Camp Steffani (River Mile 15.5) to the Carmel River Lagoon (River Mile 0.0). Annual inspections help determine the scope of work for vegetation management activities typically conducted in the fall in preparation for high winter flows, and for addressing new erosion problems and riparian ordinance violations.

                      

One area with large downed trees that could divert high flows and lead to bank erosion was observed.  In addition, several areas had vegetation encroachment that could possibly create debris dams and divert flows into banks.  All these areas will be addressed this fall.   

 

EXHIBITS

23-A    Average Dawn Leaf Water Potential

23-B    Depth to Groundwater

 

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